/*
 * Copyright 2020 by OLTPBenchmark Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package com.oltpbenchmark.distributions;

import java.util.concurrent.atomic.AtomicInteger;

/** Generates a sequence of integers 0, 1, ... */
public final class CounterGenerator extends IntegerGenerator {
  final AtomicInteger counter;

  /** Create a counter that starts at countstart */
  public CounterGenerator(int countstart) {
    counter = new AtomicInteger(countstart);
    setLastInt(counter.get() - 1);
  }

  /**
   * If the generator returns numeric (integer) values, return the next value as an int. Default is
   * to return -1, which is appropriate for generators that do not return numeric values.
   */
  public int nextInt() {
    int ret = counter.getAndIncrement();
    setLastInt(ret);
    return ret;
  }

  @Override
  public int lastInt() {
    return counter.get() - 1;
  }

  @Override
  public double mean() {
    throw new UnsupportedOperationException("Can't compute mean of non-stationary distribution!");
  }

  public void reset() {
    // TODO Auto-generated method stub
    counter.set(0);
  }
}
